8/10/2019 Aeroelasticity homework problems

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1. A uniform rigid wing section of span 1 m and chord 0.2 m is suspended in a wind-tunnel as

shown below. For the wind tunnel, static pressure and air specific heat ratio is given as

p = 40 kN/m and = 1.4, respectively. For 215.5 MCL per radian, and

LM CC 25.0 , calculate the aileron reversal Mach number.

2. UsingExcelorMATLAB,plotafamilyofcurvesthatdepictstherelationshipoftheaileronelastic

efficiency,E,versusnormalizeddynamicpressure Dqqq , for various values of DR qqR

and 10 q . You should make two plots on the following scales to reduce confusion:

a) Plot 1R using axes 33 E ,

b) Plot 1R usingaxes 33 E .

Hint:Donotcomputevaluesforthecaseswhere 1.11 R ; Excel does not handle these well.

For some cases you may want to plot symbols only and nicely sketch the lines that form the

curves.

Answer the following questions: Where does aileron reversal occur? If you had to design a

wing whatRwould you try to approach and why? What happens when DR qq ? How does

the efficiency change as qapproaches qR? Why do you think this happens? What other

pertinent features can you extract from these plots? Explain how you came to these

conclusions.

K1=5.6KN/m K2=4KN/m

x2=0.7c

U

x1=0.1c